Color fringing with Rebel XT

Archived from groups: rec.photo.digital (More info?)

I noticed something on my first processed images and wanted to see if
the was a problem with the camera, the lens or my understanding of
digital.

I shot a bright blue sky with puffy white clouds and I am getting a
thin magenta line along the break between clouds and sky in some areas.
At first I thought this was because I brightened the sky a bit using
levels but, it showed in the Raw image as well


Any suggestions would be helpful.

Also I can upload the high res image if needed

Ray

Archived from groups: rec.photo.digital (More info?)

recover wrote:
>
> I noticed something on my first processed images and wanted to see if
> the was a problem with the camera, the lens or my understanding of
> digital.
>
> I shot a bright blue sky with puffy white clouds and I am getting a
> thin magenta line along the break between clouds and sky in some areas.
> At first I thought this was because I brightened the sky a bit using
> levels but, it showed in the Raw image as well
>
> Any suggestions would be helpful.
>
> Also I can upload the high res image if needed
>
> Ray

High contrast areas are where you notice fringing the most. It can be
removed (kind of) by using Painthsop or photoshop etc. Here are the
instructions which i cut from a website (can't recall which, damnit,
so I can't give them the credit they deserve.
------------------------------------------------
remove fringing using the Hue/Saturation/Lightness (HSL) tool. For
details see the May 2003 Graphics column (available online here),
which covered some of the hidden tricks of this under-used feature. -

Instructions for using HSL to remove purple fringing will vary
slightly between programs, but they all follow the same basic process.
Start by loading up your affected image. Now go to the HSL tool. In
Photoshop, select Image-Adjustments-Hue/Saturation… In Photoshop
Elements 2, select Enhance-Adjust Color-Hue Saturation… and in Paint
Shop Pro 8 Adjust-Hue & Saturation-Hue/Saturation/Lightness.

Here is the important step: click the blue channel. Do not adjust the
master channel. Now adjust the saturation slider to around 80 per cent
(you can fine-tune this later).

If you are using Paint Shop Pro 8, move the colour wheel slowly around
and watch the preview window. When you hit the right spot, the purple
will vanish. Fine-tune the slider for maximum effect and click OK. If
there are still traces of purple, repeat the process until you find
the other tone.

The Adobe products take guesswork out of the HSL adjustment step. When
the blue channel is selected, the eye dropper tool will become
available. Click the eyedropper on the left and use it to sample the
purple fringe in your image. You can use the colour slider at the
bottom to make finer adjustments (tip: you can also use the + and -
keys to zoom in and out of the image while the HSL window is still
open).

Finally, you may find the image needs some minor tinkering and will
probably appear a little washed out. Making fine adjustments to the
Brightness/Contrast or Levels settings will correct these problems
----------------------------------------------------


--
Paul (And I'm, like, "yeah, whatever!" )
-------------------------------------------------------
Stop and Look
http://www.geocities.com/dreamst8me/

Archived from groups: rec.photo.digital (More info?)

I thought this might help. this is all of the Exif

Also it was an easy fix in PS with the Hue Sat Sliders once I knew what
to look for. I am using PS 7 so I don't think a Raw converter is
available.

Iso Speed 400

Lens 28-70 Tokina ATK Pro - No Hood

FL 28mm

WB - Auto

Shutter Speed 1/640

Ap 13.0

Shot at about 1pm on a perfect spring type day

Archived from groups: rec.photo.digital (More info?)

"rcrev" <rcrev@yahoo.com> wrote in message
news:1125017394.610266.43630@g43g2000cwa.googlegroups.com...
> I thought this might help. this is all of the Exif
>
> Also it was an easy fix in PS with the Hue Sat Sliders once I knew what
> to look for. I am using PS 7 so I don't think a Raw converter is
> available.
>
> Iso Speed 400
>
> Lens 28-70 Tokina ATK Pro - No Hood
>
> FL 28mm
>
> WB - Auto
>
> Shutter Speed 1/640
>
> Ap 13.0
>
> Shot at about 1pm on a perfect spring type day

"Lens 28-70 Tokina ATK Pro - No Hood"

Archived from groups: rec.photo.digital (More info?)

>
> I have never experienced that with my Olympus Zuiko Digital lenses.
> Canon makes nice bodies, but their lenses leave a lot to be desired.
>
>
> --
I have three Canon L series lenses, they seem to do everything their price
tag suggests they should. Are you suggesting that an Olympus lens will do
better than Canon L lenses?

John

Archived from groups: rec.photo.digital (More info?)

>
> "Lens 28-70 Tokina ATK Pro - No Hood"
>
>
>

Yes interesting, does it have a sensor to give the 'No Hood' info ?

Archived from groups: rec.photo.digital (More info?)

"Eatmorepies" <naj9daynum3@lineone.net> wrote in message
news:430ed0cc_2@mk-nntp-2.news.uk.tiscali.com...
>
>
> >
> > I have never experienced that with my Olympus Zuiko Digital lenses.
> > Canon makes nice bodies, but their lenses leave a lot to be desired.
> >
> >
> > --
> I have three Canon L series lenses, they seem to do everything their price
> tag suggests they should. Are you suggesting that an Olympus lens will do
> better than Canon L lenses?
>
> John
>
>
I have the entry level L lens, the 300 f/4 IS, I can zoom way into the
image, anywhere, and not see fringing or loss of sharpness. My 18-55 and
80-200 (consumer toy models) show some color fringing, but it is mild in
either case.

When Canon redesigned the L series fixed telephoto glass, like the 300/2.8
and the 500/4.5 a few years back, they created some incredible glass.
-S

Archived from groups: rec.photo.digital (More info?)

rcrev wrote:
>
> I noticed something on my first processed images and wanted to see if
> the was a problem with the camera, the lens or my understanding of
> digital.
>
> I shot a bright blue sky with puffy white clouds and I am getting a
> thin magenta line along the break between clouds and sky in some areas.
> At first I thought this was because I brightened the sky a bit using
> levels but, it showed in the Raw image as well
>
> Any suggestions would be helpful.
>
> Also I can upload the high res image if needed
>
> Ray

Hello

If you have a magenta fringe, then it is usually associated witha green
fringe as well.
This is correctable, especially if you use Adobe Camera Raw, which can
remove this. It is not so easily removed, from non raw images, but this
utility is pretty good. It will also correxct barrel distortion.

http://flofilters.free.fr/download.php

Mike Engles

Archived from groups: rec.photo.digital (More info?)

rcrev wrote:
>
> I noticed something on my first processed images and wanted to see if
> the was a problem with the camera, the lens or my understanding of
> digital.
>
> I shot a bright blue sky with puffy white clouds and I am getting a
> thin magenta line along the break between clouds and sky in some areas.
> At first I thought this was because I brightened the sky a bit using
> levels but, it showed in the Raw image as well
>
> Any suggestions would be helpful.
>
> Also I can upload the high res image if needed
>
> Ray


Hello
As a postscript, here is what ACR can do to a image from a Canon 20D and
a 17-85mm lens

Mike Engles

Archived from groups: rec.photo.digital (More info?)

On Fri, 26 Aug 2005 23:14:09 +0000 (UTC), Mike Engles
<mike.sengles@btinternet.com> wrote:

>Mark & Mary Ann Weiss wrote:
>>
>> "birdman" <apquilts@pacbell.net> wrote in message
>> news:A6tPe.693$5k1.197@newssvr27.news.prodigy.net...
>> > Sometimes the fringing is chromatic aberration, a problem that is common
>> in
>> > Canon wide angle lenses for their digital SLRs at the lower focal lengths.
>> > I say that because every demo I have seen of how to correct chromatic
>> > aberration using a raw converter uses images made with Canon lenses. I do
>> > not see this much using my Nikon lenses (there are plenty of other issues
>> > with Nikons to make up for it).
>>
>> I have never experienced that with my Olympus Zuiko Digital lenses.
>> Canon makes nice bodies, but their lenses leave a lot to be desired.
>>
>> --
>> Take care,
>>
>> Mark & Mary Ann Weiss
>>
>> VIDEO PRODUCTION • FILM SCANNING • DVD MASTERING • AUDIO RESTORATION
>> Hear my Kurzweil Creations at: http://www.dv-clips.com/theater.htm
>> Business sites at:
>> www.dv-clips.com
>> www.mwcomms.com
>> www.adventuresinanimemusic.com
>> -
>
>
>hello
>
>If you look closely ALL cameras/lens combination will show colour
>aberations to to a greater or lesser extent.
>The fringing can be magenta/green, red/cyan or blue/yellow.
>Olympus is no exception. It is because no lens can bring all wavelenghts
>of light to the same focus point.
>
>Mike Engles

There are some "lenses" that do correct all visible colour, but they
are not the junk made by camera mfgs. Camera lenses are corrected to
about 10-20 waves of green light. Some are much worse. There are
lenses available corrected to 1/10 wave (2x better than is needed for
"diffraction limited" performance) and are corrected for visible
colour. But, none of them are f2-f4. The fastest (telephoto) you are
ever likely to get corrected for colour would be about f5.6.
-Rich


"Bittorrents are REFUNDS for all the BAD movie products Hollywood
never gave us refunds for in the past"

Archived from groups: rec.photo.digital (More info?)

In article <430FA3F4.5BE0@btinternet.com>, Mike Engles
<mike.sengles@btinternet.com> writes
>rcrev wrote:
>>
>> I noticed something on my first processed images and wanted to see if
>> the was a problem with the camera, the lens or my understanding of
>> digital.
>>
>> I shot a bright blue sky with puffy white clouds and I am getting a
>> thin magenta line along the break between clouds and sky in some areas.
>> At first I thought this was because I brightened the sky a bit using
>> levels but, it showed in the Raw image as well
>>
>> Any suggestions would be helpful.
>>
>> Also I can upload the high res image if needed
>>
>> Ray
>
>
>Hello
>As a postscript, here is what ACR can do to a image from a Canon 20D and
>a 17-85mm lens
>
>Mike Engles

Er .... where?
--
David Littlewood